Bock

Have a stupid motor knock in a 93 5.0 that I paid $500 for...

Motor has 200k on it and has a goofy idle. When I give it gas and let off sometimes it'll die, sometimes it won't, but idle drops super low. Any ideas?

Manuellabour247

Check all of your vaccuum lines. If any look/feel brittle or broken, replace them all. It's cheap enough. Have you done any sort of tune up on it yet? (plugs, fluids, filters, etc?)

Bock

Not yet as I'm not exactly willing to drop more into something that I won't get back. If that makes sense... I mean I work at autozone, so it's cheaper, but still. Haha.

And I suppose I could try it.

Bock

Also, did remove the AF to see if it was blocked and that was causing it... That answer is no.

Manuellabour247

I'm guessing this is an unmolested truck? No lifts, swaps, or anything? If so, it should be relatively easy to find out where the knock is coming from. I'm sure there are machine shops around you that could disassemble the block, clean it, hone/bore it, and reassemble it for around a grand or 1500. That's cheap to have a good engine in your truck.

If you are pretty handy, you could tear everything down and take the bare block to them for rebuilding, then buy a kit and rebuild it yourself.

Ok, back on topic. Fuel filter, fuel pump, vaccuum lines. Those 3 things can cause the issues you're describing. That would be where I started.

Bock

Relatively unmolested. Cab vin doesn't match title... But the knock is lower driver side of the motor it seems... And I'm not sure if it's been lifted or anything previously, the guy I bought it from cut fenders to fit 35's at stock height.

I'm sure I could tear down and rebuild myself. Autozone is a part time. I work at a welding and fab shop full time on second/thirds... We have cnc's and all sorts of fun stuff. I'm just scared if I open this motor up, I'm going to get into something way over my head, and end up sinking way more money into it than it's worth... But I understand there's no way to diagnose without trying things. I'll try the filters, and the hoses first.

Ps... It usually runs fine at an idle if I don't hammer it in between..

Manuellabour247

[QUOTE=Bock;4176516]Relatively unmolested. Cab vin doesn't match title...QUOTE]

Ummm, they let you tag this? The cab VIN is what matched the title. If you swap cabs, then the title goes with the cab. This might be a problem.

Aside from the legality of that problem. If you have enough money, it would probably be better to take the whole thing to a reputable shop and let them rebuild it. If you're not comfortable with doing the job yourself, sometimes it is better to spend the money to have somebody else do it.

After you check all of your vaccuum lines and do a basic tune up, get a fuel pressure test gauge and test your fuel system. Then start diagnosing anything else that would cause these problems.

Bock

Dude I picked it up from had tags on it... They didn't seem to give him any **** about it. But, idk. It's currently sitting untagged, I'm not gonna tag it if it isn't staying. If that makes sense...

And thats a potential possibility. We'll see. I'll start with a tune up. Haha

Manuellabour247

If there's no inspection then you shouldn't have to worry about it. If you ever get pulled over and they check the VIN, that's where it could get really interesting. Lol. But I agree, start with a tune up.

Matthew Burr

no smoke from the exhaust or unexplained loss of coolant?